Changes for Web developers

Developer Tools

Anywhere a DOM node appears in the console output, it is highlighted when you hover over that console output (bug 757866). Similarly all JS functions and objects are highlighted in the console output (bug 584733). More information about the console improvement can be found in this blog post.

Added support for a new value (alpha) for the second, optional, parameter of the HTMLCanvasElement.getContext() method allowing to define if alpha blending must be stored or not for this context. When not, the per-pixel alpha value in this store is always 1.0. This allows the back-end to implement a fast-track. (bug 982480)

MathML

SVG

Audio/Video

On Linux, Gstreamer 1.0 is now supported (instead of 0.10) (bug 806917).

Security

No change.

Changes for add-on and Mozilla developers

The interface nsIDOMWindowUtils now supports the Boolean attribute audioMuted and audioVolume, a float in the range [0.0 , 1.0], allowing to control the sound produced by a window (that is any tab or iframe). There is no UI for this, but is available to add-ons. (bug 923247)